ceph/src/boost/libs/geometry/example/01_point_example.cpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
   4 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
   5 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
   6
   7 // Use, modification and distribution is subject to the Boost Software License,
   8 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10 //
  11 // Point Example - showing different type of points
  12
  13 #include <iostream>
  14
  15 #include <boost/geometry/geometry.hpp>
  16 #include <boost/geometry/geometries/point_xy.hpp>
  17 #include <boost/geometry/geometries/adapted/boost_tuple.hpp>
  18 #include <boost/geometry/geometries/adapted/c_array.hpp>
  19 #include <boost/geometry/geometries/adapted/boost_array.hpp>
  20 #include <boost/geometry/geometries/adapted/boost_polygon/point.hpp>
  21
  22 BOOST_GEOMETRY_REGISTER_C_ARRAY_CS(cs::cartesian)
  23 BOOST_GEOMETRY_REGISTER_BOOST_ARRAY_CS(cs::cartesian)
  24 BOOST_GEOMETRY_REGISTER_BOOST_TUPLE_CS(cs::cartesian)
  25
  26
  27 int main()
  28 {
  29     using namespace boost::geometry;
  30
  31     // Boost.Geometry contains several point types:
  32     // 1: its own generic type
  33     model::point<double, 2, cs::cartesian> pt1;
  34
  35     // 2: its own type targetted to Cartesian (x,y) coordinates
  36     model::d2::point_xy<double> pt2;
  37
  38     // 3: it supports Boost tuple's
  39     boost::tuple<double, double> pt3;
  40
  41     // 4: it supports normal arrays
  42     double pt4[2];
  43
  44     // 5: it supports arrays-as-points from Boost.Array
  45     boost::array<double, 2> pt5;
  46
  47     // 6: it supports points from Boost.Polygon
  48     boost::polygon::point_data<double> pt6;
  49
  50     // 7: in the past there was a typedef point_2d
  51     //    But users are now supposted to do that themselves:
  52     typedef model::d2::point_xy<double> point_2d;
  53     point_2d pt7;
  54
  55
  56     // 7: there are more variants, and you can create your own.
  57     //    (see therefore the custom_point example)
  58
  59     // All these types are handled the same way. We show here
  60     // assigning them and calculating distances.
  61     assign_values(pt1, 1, 1);
  62     assign_values(pt2, 2, 2);
  63     assign_values(pt3, 3, 3);
  64     assign_values(pt4, 4, 4);
  65     assign_values(pt5, 5, 5);
  66     assign_values(pt6, 6, 6);
  67     assign_values(pt7, 7, 7);
  68
  69
  70     double d1 = distance(pt1, pt2);
  71     double d2 = distance(pt3, pt4);
  72     double d3 = distance(pt5, pt6);
  73     std::cout << "Distances: "
  74         << d1 << " and " << d2 << " and " << d3 << std::endl;
  75
  76     // (in case you didn't note, distances can be calculated
  77     //  from points with different point-types)
  78
  79
  80     // Several ways of construction and setting point values
  81     // 1: default, empty constructor, causing no initialization at all
  82     model::d2::point_xy<double> p1;
  83
  84     // 2: as shown above, assign_values
  85     model::d2::point_xy<double> p2;
  86     assign_values(p2, 1, 1);
  87
  88     // 3: using "set" function
  89     //    set uses the concepts behind, such that it can be applied for
  90     //    every point-type (like assign_values)
  91     model::d2::point_xy<double> p3;
  92     set<0>(p3, 1);
  93     set<1>(p3, 1);
  94     // set<2>(p3, 1); //will result in compile-error
  95
  96
  97     // 3: for any point type, and other geometry objects:
  98     //    there is the "make" object generator
  99     //    (this one requires to specify the point-type).
 100     model::d2::point_xy<double> p4 = make<model::d2::point_xy<double> >(1,1);
 101
 102
 103     // 5: for the d2::point_xy<...> type only: constructor with two values
 104     model::d2::point_xy<double> p5(1,1);
 105
 106     // 6: for boost tuples you can of course use make_tuple
 107
 108
 109     // Some ways of getting point values
 110
 111     // 1: using the "get" function following the concepts behind
 112     std::cout << get<0>(p2) << "," << get<1>(p2) << std::endl;
 113
 114     // 2: for point_xy only
 115     std::cout << p2.x() << "," << p2.y() << std::endl;
 116
 117     // 3: using boost-tuples you of course can boost-tuple-methods
 118     std::cout << pt3.get<0>() << "," << pt3.get<1>() << std::endl;
 119
 120     // 4: Boost.Geometry supports various output formats, e.g. DSV
 121     //    (delimiter separated values)
 122     std::cout << dsv(pt3) << std::endl;
 123
 124     // 5. or wkt
 125     std::cout << wkt(p4) << (equals(p4, p5) ? " equals " : " don't equals ") << wkt(p5) << std::endl;
 126
 127     // There are 3-dimensional points too
 128     model::point<double, 3, cs::cartesian> d3a, d3b;
 129     assign_values(d3a, 1, 2, 3);
 130     assign_values(d3b, 4, 5, 6);
 131     d3 = distance(d3a, d3b);
 132
 133
 134
 135     // Other examples show other types of points, geometries and more algorithms
 136
 137     return 0;
 138 }